Author
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Laird, David |
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Submitted to: Clays and Clay Minerals
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 6/12/1996 Publication Date: N/A Citation: N/A Interpretive Summary: The quality of a soil depends largely on the type of mineral particles within the soil. Some soil minerals swell when they imbibe water and shrink when they dry out. A little shrinking and swelling of soil minerals improves soil quality by opening up pores so the soil can breathe. On the other hand, too much shrinking and swelling can plug the soil pores, break plant roots, and even buckle foundations. We have developed a new model of how and why soil minerals swell during the early stage of the swelling process. The model predicts the general swelling behavior of soil minerals and helps define knowledge gaps that still must be filled for a complete understanding of mineral swelling. Technical Abstract: A macroscopic energy balance model for crystalline swelling of 2:1 phyllosilicates is presented. A numerical solution of the model is shown to yield reasonable estimates of basal spacings for octahedrally charged clays. Measured and predicted basal spacings are directly compared and shown to be in general agreement (r**2=0.39). Most of the scatter in the measured vs. predicted basal spacing relationship is attributed to the fact that the numerical solution does not adequately account for the free energy of resistance. The crystalline swelling model readily accounts for the effects of layer charge and nature of the interlayer cations on crystalline swelling, but does not account for the effect of charge site location on crystalline swelling. |
